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Modulated and composite structures dictionary (msCIF) version 1.0.1

Category ATOM_SITE_ROT_FOURIER_PARAM

Name:
'_atom_site_rot_Fourier_param_[]'

Definition:

   Data items in the ATOM_SITE_ROT_FOURIER_PARAM category record
   details about the coefficients of the Fourier series used to
   describe the rotational component of the displacive modulation of
   a given rigid group. The translational part would appear in a
   separate list of items belonging to the
   ATOM_SITE_DISPLACE_FOURIER_PARAM category. The Fourier components
   are defined in the category ATOM_SITE_ROT_FOURIER and are listed
   separately.

Examples:

Example 1 - example corresponding to the one-dimensional incommensurately modulated structure of K~2~SeO~4~. 
 
     loop_
         _atom_site_rot_Fourier_param_id
         _atom_site_rot_Fourier_param_cos
         _atom_site_rot_Fourier_param_sin
              SeO4_x_1    -4.2(1)   0.91(3)
              SeO4_y_1     4.3(1)   0.


Example 2 - extracted from Baudour & Sanquer [Acta Cryst. (1983), B39, 75-84]. Note the entry from the ATOM_SITES_ROT_FOURIER category to describe collective information relating to all the atom sites. 
 
     _atom_sites_rot_Fourier_axes_description
     ;   a1 and a2 are respectively the long molecular axis
         and the axis normal to the mean molecular plane.
     ;
     loop_
         _atom_site_rot_Fourier_param_id
         _atom_site_rot_Fourier_param_modulus
         _atom_site_rot_Fourier_param_phase
              Ph1_a1_1  11.0(2)  0.
              Ph2_a1_1  11.0(2)  0.5
              Bph_a2_1   1.0(1)  0.25


Type: null

Category: category_overview


International Tables for Crystallography

Volume G: Definition and exchange of crystallographic data

First online edition (2006)

Edited by S. R. Hall and B. McMahon

An essential guide and reference to CIF for programmers, data managers handling crystal-structure information and practising crystallographers.